XFS defragmentation issue

[John Lister]

  Stan Hoeppner wrote on 9/10/2010 14:00
 >>On 10/09/2010 15:41, John Lister wrote:
 >> Hi, using ubuntu 9.04, kernel version 2.6.28-18 and xfsprog 
v2.10.2-1 I'm trying to defragment a drive. If I use xfs_db to check for 
fragmentation it shows for >>example that a file has 20k+ fragments:
 >>inode 578505506 actual 23240 ideal 1
 >>
 >>mapping the inode to the file and running xfs_frs states that the 
file is fully defragmented.
 >>
 >>Also running xfs_frs says the drive is defragmented while xfs_db for 
example reports 300k fragments.
 >>
 >>Which is right? and is it possible to defragment the file assuming it 
is fragmented so badly, if so how?

 >Try unmounting and remounting the filesystem, and see if the various
 >tools all report the same thing afterwards. This solved the exact same
 >problem for me very recently, though I'm on kernel 2.6.34.1 and xfsprogs
 >2.9.8.

Cheers, that got rid of most of it, there is still a slight discrepency  
(50 extra fragments) which I can live with.

John